Linux PCI subsystem development
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From: Hans Zhang <18255117159@163.com>
To: lpieralisi@kernel.org
Cc: manivannan.sadhasivam@linaro.org, thierry.reding@gmail.com,
	kw@linux.com, robh@kernel.org, bhelgaas@google.com,
	jonathanh@nvidia.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
	Hans Zhang <18255117159@163.com>
Subject: [PATCH] pci: tegra194: Fix debugfs cleanup for !CONFIG_PCIEASPM
Date: Sat,  5 Apr 2025 22:54:59 +0800	[thread overview]
Message-ID: <20250405145459.26800-1-18255117159@163.com> (raw)

When CONFIG_PCIEASPM is disabled, debugfs entries are not created, but
tegra_pcie_dw_remove() and tegra_pcie_dw_shutdown() unconditionally call
debugfs_remove_recursive(), leading to potential NULL pointer operations.

Introduce deinit_debugfs() to wrap debugfs_remove_recursive(), which is
stubbed for !CONFIG_PCIEASPM. Use this function during removal/shutdown to
ensure debugfs cleanup only occurs when entries were initialized.

This prevents kernel warnings and instability when ASPM support is
disabled.

Signed-off-by: Hans Zhang <18255117159@163.com>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 5103995cd6c7..d762e733c2d8 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -716,11 +716,20 @@ static void init_debugfs(struct tegra_pcie_dw *pcie)
 	debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt", pcie->debugfs,
 				    aspm_state_cnt);
 }
+
+static void deinit_debugfs(struct tegra_pcie_dw *pcie)
+{
+	if (!pcie->debugfs)
+		return;
+
+	debugfs_remove_recursive(pcie->debugfs);
+}
 #else
 static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { return; }
 static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { return; }
 static inline void init_debugfs(struct tegra_pcie_dw *pcie) { return; }
+static inline void deinit_debugfs(struct tegra_pcie_dw *pcie) { return; }
 #endif
 
 static void tegra_pcie_enable_system_interrupts(struct dw_pcie_rp *pp)
@@ -2289,7 +2298,7 @@ static void tegra_pcie_dw_remove(struct platform_device *pdev)
 		if (!pcie->link_state)
 			return;
 
-		debugfs_remove_recursive(pcie->debugfs);
+		deinit_debugfs(pcie->debugfs);
 		tegra_pcie_deinit_controller(pcie);
 		pm_runtime_put_sync(pcie->dev);
 	} else {
@@ -2408,7 +2417,7 @@ static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
 		if (!pcie->link_state)
 			return;
 
-		debugfs_remove_recursive(pcie->debugfs);
+		deinit_debugfs(pcie->debugfs);
 		tegra_pcie_downstream_dev_to_D0(pcie);
 
 		disable_irq(pcie->pci.pp.irq);

base-commit: a8662bcd2ff152bfbc751cab20f33053d74d0963
-- 
2.25.1


             reply	other threads:[~2025-04-05 14:55 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-05 14:54 Hans Zhang [this message]
2025-04-05 15:28 ` [PATCH] pci: tegra194: Fix debugfs cleanup for !CONFIG_PCIEASPM Bjorn Helgaas
2025-04-05 15:49   ` Hans Zhang
2025-04-05 16:17     ` Christophe JAILLET
2025-04-05 16:35       ` Hans Zhang
2025-04-05 16:47         ` Hans Zhang
2025-04-05 17:04           ` Christophe JAILLET
2025-04-05 17:10             ` Hans Zhang
2025-04-05 16:14 ` Christophe JAILLET
2025-04-05 16:41   ` Hans Zhang
2025-04-06  0:48 ` kernel test robot
2025-04-06  2:10 ` kernel test robot

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